WASHINGTON (WHP) -- Be on the lookout for a sure sign of fall this weekend.

Sunday evening stargazers can expect to see a bright orange moon appear in the night sky. Full moons occur about once a month. They happen when Earth is positioned directly between the moon and the sun.

The moon will be visible after sunset on Sunday night at 6:31 p.m. EDT.

If skies are clear, there is a good chance the October "Full Hunter's Moon" will appear large and more orange due to the fact that it will be visible at the time of sunset.

A trick of the eyes, known as the "moon illusion," makes the moon appear larger near the horizon than when it's positioned higher in the sky.

Unlike some of the other full moon names, the "Hunter's Moon" is not tied to a specific month. The name is given to whichever full moon comes after the "Harvest Moon," or the one closest to the autumn equinox in the Northern Hemisphere.